<p>This paper deals with the interconnected grid hybrid renewable energy system (HRES). The wind energy conversion system (WECS), is built around a wind turbine coupled to a doubly fed induction generator (DFIG). The stator of DFIG is directly related to the grid and the rotor is connected to the grid through back-to-back power converters. The proposed algorithm combines the nonlinear Backstepping approach and the eld orientation applied to control the DFIG. In a rst step, this technique is applied to the side converter rotor (RSC), to control the electromagnetic torque and reactive power, and secondly, it is applied to the grid side converter (GSC) to control the power exchanged with the grid and regulate the DC bus voltage. The PV energy system is composed by the PV array and the DC-DC boost converter which controlled by the MPPT method to extract the optimal power. Simulations results present the performances in terms of set point tracking, stability, and robustness with respect to the variation in wind speed and irradiation.</p>

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Abstract:In this paper, an induction machine rotor speed and rotor flux control using a sensorless backstepping control scheme is discussed. The most interesting point of this technique is that it deals with the nonlinearity of a high-order system by using the virtual control variable to make this system simple, and thus the control outputs can be derived step by step through appropriate Lyapunov functions. To avoid the use of a mechanical sensor, the rotor speed estimation is made by an observer using the model reference adaptive system (MRAS) technique; in order to estimate rotor flux, a sliding mode observer is proposed in this work. Simulation results are presented to validate and prove the effectiveness of the proposed sensorless control.

<p>To accommodate the regularity of wind energy; a storage device is required for the wind turbine. This paper proposesa constant power control for wind farm based Doubly Fed Induction Generator, the suggested storage device is supercapacitor which is connected to every wind turbine of the wind farm, it provides output power stability and compensates the deviations between the available wind energy input and the desired active power output. A Distribution – Static Synchronous Compensator (D-STATCOM) is connected at the point of connection of the wind farm, it controls the active and reactive power according to the demand from orpower generation to the electrical grid. The coordinated approach between the supercapacitors and the D-STATCOM mitigates the voltage magnitude fluctuations of the wind farm and provides support to the active power. Simulation studies are carried out inMATLAB/Simulink.

<p><span lang="EN-US">In this paper we are interested in optimizing the wind power capture, using the Doubly Fed Induction Generator (DFIG). This machine is preferred to other types of variable speed generator because of their advantages in economic terms and control. The Artificial Neural Network (ANN) based on Direct Torque Control (DTC) which is used to control the electromagnetic torque in order to extract the maximum power, The  main  objective  of this intelligent technique is to replace the conventional switching table  by  a  voltage  selector  based  on  (ANN)  to  reduce torque  and  flux  ripples. Moreover, the fuzzy logic controller is used to grid side converter to keep DC link voltage constant, and also to achieve unity power factor operation. The main advantage of the two control strategies proposed in this paper is that they are not influenced by the variation of the machine parameter. The pitch control is also presented to limit the generator power at its rated value. Simulation results of 1,5 MW, for (DFIG) based Wind Energy Conversion System (WECS) confirm the effectiveness and the performance of the global proposed approaches.</span></p>

In this paper we present the control system of a wind turbine based doubly fed induction generator (DFIG) by direct torque control (DTC). The wind energy conversion system (WECS) equipped with wind turbine, DFIG, DC bus and the power convector. The converter is controlled to generate the maximum power from wind turbine generator (WTG) by using maximum power point tracking (MPPT) strategy. The pitch control is also proposed to limit the generator power at its rated value. The DTC is developed to regulate the flux and torque. The simulation results of a 1.5MW doubly fed induction generator show the performances of the control strategy proposed. These results are validated by using the MATLAB/Simulink environment Keywords-Doubly fed induction generator (DFIG); direct torque control (DTC); Maximum power point tracking (MPPT); wind turbine generator (WTG); wind energy conversion system (WECS) I.

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